1. Field of the Invention
The present invention relates to an inorganic composition, to a composite composition containing the above inorganic composition and, particularly, to a composite composition suited for dental applications. More specifically, the invention provides a composite composition that is suitably used for obtaining a composite cured product for dental applications, having excellent wear resistance, smoothness and mechanical strength.
2. Prior Art
A composite composition such as a composite restorative for dental applications has heretofore been used in a manner that a photo-initiation catalyst is added to an acrylic ester monomer liquid which is chiefly composed of a bisphenol A glycidyl methacrylate (addition product of bisphenol A and glycidyl methacrylate, hereinafter simply referred to as Bis-GMA), which is then blended with an inorganic filler in large amounts, so that the blend is cured with light in the oral cavity. Such a restorative has been widely used among the clinicians since its appearance is close to natural teeth compared with restoratives which are chiefly composed of a metal.
Such composite restoratives for dental applications can roughly be divided into two kinds. One is a dental composite restorative which has excellent mechanical strength and wear resistance by blending an inorganic composition having a relatively large particle diameter as a filler at a large ratio as disclosed in Japanese Laid-Open Patent Publication No. 197311/1991. The other one is a dental composite restorative which has excellent surface smoothness and wear resistance of antagonistic tooth by blending an inorganic composition having a relatively small particle diameter as a filler. Here, excellent wear resistance of antagonistic tooth means that the dental composite restorative that is charged and cured in the oral cavity does not cause the antagonistic tooth to be worn out by the occlusion.
However, the conventional cured products of dental composite restoratives are not capable of fully satisfying all of the above-mentioned features, i.e., mechanical strength, wear resistance, surface smoothness and wear resistance of antagonistic tooth.